Word Origin and History for gratis. mid c., “for nothing, freely,” from Latin gratis, contraction of gratiis “for thanks,” hence, “without recompense,” ablative of gratiae “thanks,” plural of gratia “favor” see grace . Meaning “free of charge” is s. Slang definitions phrases for gratis..Free gratis definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. Look it up now!.Definition of gratis without charge free..Gratis definition If something is done or provided gratis , it does not have to be paid for. | Meaning, pronunciation, translations and examples..